In an experiment aimed at evaluating the effect of a memory-enhancing drug on the recall of a previously learned response. Either the drug or a placebo was administered to different groups of rats before the memory test. There were three trials of the memory test, and the dependent variable was the time it took the animal to make the correct response.
What assumption(s) would we need to make for this analysis?
A) The observations are independent.
B) The observations are normally distributed.
C) The animals are randomly assigned to drug treatments
D) both b and c

Question

Quizplus · Accepted Answer

We need to assume that the observations are normally distributed, and that the animals were randomly assigned to the drug treatments to ensure that any observed differences between the groups are due to the drug and not some other confounding variable. We also need to assume that the observations are independent, as each animal’s performance in the memory test is not affected by the performance of any other animal.

In an Experiment Aimed at Evaluating the Effect of a Memory-Enhancing